<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <meta name="keywords" content="HTML, CSS, XML, XHTML, JavaScript">
        <meta name="description" content="Test on HTML and CSS">
        <meta name="author" content="Huoty">
        <meta http-equiv="refresh" content="30">
        <title>Web 设计</title>
        <link rel="shortcut icon" href="http://konghy.cn/favicon.ico" type="image/x-icon" />
    </head>
    <body>
        JavaScript <span style="color:#F00">json</span> 操作
    </body>
</html> 
<script type="text/javascript">
var json = {"status": 200, "data": {"total": 1024, "usage": 248}};

if (!"data" in json) {
    console.info("data not in json");
} else {
    console.info("data in json");
    console.info(json.status);
    console.info(json['data']['total']);
    console.info(json['data']['usage']);

    console.info((1/3).toFixed(2));
    console.info((1).toFixed(2));

    console.info( 920 / 10 > 90 )
}


</script>
